The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of forming a capacitor.
Recently, as integration of semiconductor devices has become high in recent years, cell size has been reduced so that it is difficult to form a capacitor having sufficient capacitance. Particularly, in dynamic random access memories (DRAMs) which include unit cells constituting of one MOS transistor and one capacitor, reduction in dimension becomes an important factor in high integration along with increased capacitance of the capacitor which uses a large chip area.
As described above, the capacitor includes a lower electrode, an upper electrode and a dielectric layer disposed there between. In order to increase the capacitance of the capacitor, it must form the dielectric layer of a high dielectric material, reduce the thickness of the dielectric layer or increase a surface area of the electrode.
According to this, a cylinder structure in the capacitor being capable of providing a larger surface area has been suggested.
The cylinder structure is formed by forming a hole in which an electrode of a capacitor is to be formed in an insulating layer, forming a lower electrode of the capacitor within the hole, removing the insulating layer which is used as a sacrificial layer, and sequentially depositing a dielectric layer and an upper electrode along a surface of the lower electrode. Accordingly, the cylinder structure can use both inner and outer surfaces of the lower electrode as an effective surface of the capacitor so that it is possible to form the capacitor having a larger capacitance in a given area than a concave structure.